IT was in this week in 1728 that Joseph Black, the scientist who was one of the great figures of the Scottish Enlightenment, was born. I am often asked about the Scottish Enlightenment and how and why it happened. There is no single explanation as to why the Enlightenment occurred in the latter half of the 18th century, but without a doubt it was the Scottish love of education – that “school in every parish” so beloved of John Knox and the Reformers – as well as a relative meritocracy which encouraged original thinkers to develop their theories.

They often did so together, and encouraged each other. While there have often been concentrations of great minds in one place at one time, never was there a more diverse bunch of geniuses doing their thinking in one small well-connected country than happened in Scotland during the Enlightenment.

Joseph Black, who is buried in Greyfriars Kirkyard in Edinburgh and has the chemistry buildings of both Glasgow and Edinburgh universities named after him, was a great example of an Enlightenment genius.

He was born the son of an Ulsterman of Scottish descent, John Black, and a Scottish mother, Margaret nee Gordon, both of whose families were in the wine trade, hence Black’s birthplace of Bordeaux in France on April 16, 1728.

He was one of at least a dozen children, and was educated at first by his mother who had been schooled at home in Aberdeen. Black was sent to Belfast for formal education at the age of 12 and four years later he matriculated at Glasgow University and began to study the arts, before switching to medicine to satisfy his father’s request that he study something useful.

William Cullen was the renowned professor of medicine at Glasgow at this time, but it was another subject that he taught which made a profound impression on the young Black.

Black wrote later about this most useful coincidence: “Dr Cullen about this time began also to give lectures in chemistry which had never been taught in the University of Glasgow and finding that I might be useful to him in that Undertaking he employed me as his assistant in the laboratory.”

Edinburgh was the world’s most important medical teaching institution at that time, so Black went eastwards in 1752 to complete his medical studies. While still a student he devised a new analytical balance which was far more accurate than any other weighing device of this type, and soon became the standard of its type in laboratories. It was an invention that was typical of Black’s working approach – a meticulous observer and prodigious note-taker and recorder of experiments who valued accuracy above all else.

Again while still a student, Black wrote a thesis on magnesium carbonate which included his discovery of what he called ‘fixed air’ and which we now know as carbon dioxide.

His experiments laid the foundation for modern chemistry, as he recorded weight changes and other data when the magnesium carbonate was burned or the products of this burning reacted with acids or alkalis.

Not forgetting his medicine, Black included a section on magnesium carbonate as an antacid and purgative – think Rennies or Milk of Magnesia and you’ll get the gist of his innovative thinking. He repeated his experiments with calcium and thus became the first chemist in the world to prove that gases could be chemical substances in themselves.

Black returned to Glasgow University in 1756 and became professor of medicine there a year later. Around this time he met and became friends with James Watt, the steam engine pioneer. Their letters to each other over many years have survived and show the genius of both men – just as well they were kept, as Black often refused to publish his research.

Even before their discussions Black had begun to develop his theories of latent heat, and his experiments and deductions are recognised as the foundation of the science of thermodynamics.

Black returned to Edinburgh in 1766 and turned his attention to being a physician as well as teaching. He gave lectures that included famous experiments for which students from all over Europe and America were happy to pay. Many of his students disseminated his work and among them was Daniel Rutherford, who discovered nitrogen.

He also took to helping the rapid industrialisation of Scotland – Black had a job examining the many new inventions of the time to see if they could get a government grant and he was soon described as the “best judge, perhaps in Europe” of these developments.

He knew and discussed a huge range of issues with Enlightenment figures such as the philosopher David Hume – he was his personal doctor – and Wealth of Nations author Adam Smith. Black also became a firm friend of the founder of the science of geology, James Hutton, and in a curious way he possibly saved the life of the young Sir Walter Scott – Black diagnosed that Scott’s nurse was developing tuberculosis and she was removed from the boy.

Black was no cloistered intellectual. He was a member of Edinburgh’s Oyster and Poker clubs, he played the flute and enjoyed the company of women though he never married, possibly because of his near lifelong ill health which included rheumatism from an unusually early age.

Joseph Black died at his home in Edinburgh on December 6, 1799. He was found dead in his chair, a cup of milk perched between his knees. In the manner of his experiments, not a drop had been spilt.